iOS动态验证码实现代码

//
// AuthcodeView.h
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017年 ZTracy. All rights reserved.
//
#import 
@interface AuthcodeView : UIView
@property (strong, nonatomic) NSArray *dataArray;//字符素材数组
@property (strong, nonatomic) NSMutableString *authCodeStr;//验证码字符串
@end
//
// AuthcodeView.m
// BSbracelet
//
// Created by Christopher on 17/5/16.
// Copyright © 2017年 ZTracy. All rights reserved.
//
#import "AuthcodeView.h"
#define kRandomColor [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1.0];
#define kLineCount 6
#define kLineWidth 1.0
#define kCharCount 4
#define kFontSize [UIFont systemFontOfSize:arc4random() % 5 + 15]
@implementation AuthcodeView
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
  // Drawing code
}
*/
- (instancetype)initWithFrame:(CGRect)frame
{
  self = [super initWithFrame:frame];
  if (self)
  {
    self.layer.cornerRadius = 5.0f;
    self.layer.masksToBounds = YES;
    self.backgroundColor = kRandomColor;
    [self getAuthcode];//获得随机验证码
  }
  return self;
}
#pragma mark 获得随机验证码
- (void)getAuthcode
{
  //字符串素材
  _dataArray = [[NSArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",nil];
  _authCodeStr = [[NSMutableString alloc] initWithCapacity:kCharCount];
  //随机从数组中选取需要个数的字符串，拼接为验证码字符串
  for (int i = 0; i < kCharCount; i++)
  {
    NSInteger index = arc4random() % (_dataArray.count-1);
    NSString *tempStr = [_dataArray objectAtIndex:index];
    _authCodeStr = (NSMutableString *)[_authCodeStr stringByAppendingString:tempStr];
  }
}
#pragma mark 点击界面切换验证码
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  [self getAuthcode];
  //setNeedsDisplay调用drawRect方法来实现view的绘制
  [self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
  [super drawRect:rect];
  //设置随机背景颜色
  self.backgroundColor = kRandomColor;
  //根据要显示的验证码字符串，根据长度，计算每个字符串显示的位置
  NSString *text = [NSString stringWithFormat:@"%@",_authCodeStr];
  CGSize cSize = [@"A" sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20]}];
  int width = rect.size.width/text.length - cSize.width;
  int height = rect.size.height - cSize.height;
  CGPoint point;
  //依次绘制每一个字符,可以设置显示的每个字符的字体大小、颜色、样式等
  float pX,pY;
  for ( int i = 0; i